Polysight™

Engineered Thermoplastic Magnetic Level Gauges

Designed for corrosive chemical service, Polysight™ magnetic level gauges provide reliable, non-invasive level indication in applications where conventional sight glasses are prone to attack, fouling, or premature failure.

Polysight utilizes a magnetically coupled float and external indicator to eliminate direct contact between the process fluid and the visual indication. This design improves operator safety and ensures consistent readability in services involving vapors, scaling, or chemically aggressive media.

Purpose-built for longevity, the Polysight chamber is fabricated from chemically inert thermoplastics engineered to withstand aggressive acids, alkalis, and salts. Whether handling Hydrochloric Acid, Sodium Hypochlorite, or caustic alkalis, Polysight provides a lightweight yet durable alternative to heavy alloy gauges, simplifying installation and extending asset life.


Specifications at a Glance

  • Construction: High-performance engineered thermoplastics including PVC, CPVC, and PVDF.

  • Pressure Rating: Full vacuum to 150 psig (10 bar)

  • Operating Temperature: Service range from –20°C to +120°C (–4°F to +248°F).

  • Specific Gravity: Capable of measuring fluids with SG as low as 0.59.

  • Measuring Length: Standard ranges up to 18.5 ft (5.6 m) with extended lengths available.

  • Indication: High-visibility PVC flag or roller indicators with non-invasive magnetic coupling.

Request a Quote

Polysight: The Shatter-Proof Alternative to Traditional Sight Glasses.

A sealed magnetic level solution engineered for aggressive chemical media with full compatibility for LevelSync™ automation and SurePoint™ level switches.

Zero-Corrosion Engineering: The Inert Advantage

Traditional 316L Stainless Steel, while robust, is susceptible to pitting and stress-corrosion cracking when exposed to high-chloride environments or aggressive acids like HCl and Bleach.

  • The Polysight Edge: By utilizing high-molecular-weight thermoplastics (PVC, CPVC, and PVDF), the gauge chamber remains chemically inert. Unlike lined steel, Polysight features a solid, homogenous construction that cannot delaminate or permeate.

  • Engineering Impact: This eliminates the "corrosion allowance" guesswork. Our PVDF models, in particular, provide unmatched resistance to high-concentration sulfuric and hydrofluoric acids where even exotic alloys like Hastelloy® can struggle.

Seamless Automation: LevelSync™ & SurePoint™ Integration

Choosing a thermoplastic gauge does not mean sacrificing remote monitoring or control capabilities.

  • The Polysight Edge: The Polysight chamber is designed for the easy integration of LevelSync™ transmitters and SurePoint™ switches. These accessories are externally mounted and magnetically actuated by the internal float, allowing for signal integration without additional vessel penetrations.

  • Engineering Impact: You achieve continuous 4-20 mA level measurement and point-level alarming while maintaining a fully sealed pressure boundary. Installation and calibration can be performed while the vessel is live, avoiding costly process shutdowns.

High-Visibility Monitoring: Clear Visual Verification

Traditional glass sight gauges are notorious for fouling, fogging, or becoming opaque over time due to process coating or condensation.

  • The Polysight Edge: Because the indicator is mounted externally and magnetically coupled to the float, it never touches the process media. High-contrast flags provide a clear, bright level indication that remains readable from a distance.

  • Engineering Impact: This provides a permanent, maintenance-free visual reference that cannot cloud or stain, ensuring operators can verify levels instantly without approaching hot or hazardous equipment.

Shatter-Proof Safety: Redefining the Pressure Boundary

Standard reflex and transparent glass gauges rely on long, compressive sealing surfaces between the glass, gasket, and body. Under thermal cycling or vibration, these are frequent failure points that lead to hazardous leaks.

  • The Polysight Edge: Polysight replaces fragile glass with a solid, sealed thermoplastic pressure boundary. The liquid is completely contained within the chamber; the level is transmitted magnetically to an external, non-wetted indicator.

  • Engineering Impact: This "all-plastic" magnetic design meets the safety requirements of modern chemical facilities looking to eliminate glass from the process line entirely, significantly reducing environmental liability and personnel risk.

Engineered for Aggressive Chemical Service

From bleach storage to acid dosing, Polysight delivers impervious reliability where standard alloys fail.

Sodium hypochlorite (bleach) causes rapid oxidation and stress-corrosion cracking in stainless steel. Polysight utilizes chemically inert PVC and PVDF chambers to provide an impervious wetted path. The sealed magnetic design eliminates the risk of glass breakage and prevents salt crystallization from fouling the visual indicator.

Sodium Hypochlorite Storage

Chemical Feed & Dosing Skids

Wastewater treatment relies on aggressive reagents like Ferric Chloride and Sulfuric Acid that rapidly degrade metal components. Polysight offers OEM skid manufacturers a lightweight, corrosion-proof solution that simplifies installation. Integrated non-wetted transmitters and switches provide reliable automation for pH adjustment systems without compromising the pressure boundary.

Mineral Acid Storage

Safely manages Hydrochloric and Sulfuric acids that cause rapid failure in 316SS and typically require expensive exotic alloys.

Fertilizer & Ag-Chem

Withstands nitrogen-based fertilizers and phosphoric acid within challenging outdoor or high-humidity agricultural environments.

Ultra-Pure & DI Water

Inert thermoplastic chambers prevent ionic leaching and metallic contamination, maintaining strict fluid purity standards.

Brine & Seawater

Eliminates the pitting and crevice corrosion common in metallic gauges, making it ideal for desalination and marine ballast systems.

Automation & Integration

Transform Local Indication into Total Process Control

Upgrade your Polysight™ gauge with non-invasive automation. By clamping LevelSync™ transmitters and SurePoint™ switches externally to the chamber, you achieve advanced monitoring capabilities without adding leak paths or exposing electronics to corrosive fumes.

Because all components are non-wetted, installation and calibration can be performed while the vessel is live, avoiding costly downtime.

LevelSync™

Continuous Level Transmitters

The LevelSync™ magnetostrictive transmitter delivers high-accuracy, continuous level data (4-20 mA / HART) by tracking the float’s magnetic field through the chamber wall. Because the sensor never touches the liquid, it offers immune reliability against chemical attack, coating, or scaling that typically fouls immersion probes.

View LevelSync™ Details

Secure your process with reliable high/low-level alarms and pump control. SurePoint™ switches mount externally and can be adjusted instantly anywhere along the scale without shutting down the vessel. They serve as the perfect redundant safety backup independent of your primary control loop.

Point Level Switches

SurePoint™

View SurePoint™ Details

MagnaLine™ Float Technology

At the core of the gauge is the MagnaLine™ float. Engineered for stability, each float utilizes a high-strength, 360-degree magnetic flux assembly designed to maximize coupling force with the external indicator. This design ensures robust signal retention during standard operation and minimizes the risk of decoupling during process fluctuations.

Because accuracy depends on physics, every MagnaLine float is precision-weighted to the exact Specific Gravity (SG) and operating pressure of your fluid. Whether utilizing Titanium for high-pressure service or Stainless Steel for standard applications, we engineer the float to maintain the correct buoyancy relative to the fluid density, ensuring the indicated level matches the true process level.

Optional FloatSense™ Technology

Real-Time Float Integrity Monitoring

Eliminate the "blind spot" in level measurement. FloatSense™ provides early detection of float anomalies. In critical applications, this diagnostic feature warns operators if a float has been compromised or is failing to track, allowing for proactive maintenance before a process upset occurs.

  • Solid Thermoplastic MagnaLine Float

    Constructed from solid PVDF, PVC, or PP to provide impervious resistance to aggressive acids and caustics.

  • Syntactic Foam MagnaLine Float

    Syntactic foam float for ultra-high-pressure process applications.

  • PTFE (Teflon®) Coated MagnaLine Float

    PTFE-coated float for highly corrosive chemical service.

  • Titanium MagnaLine Float

    High-strength titanium offering superior buoyancy-to-weight ratio for precision tracking in low-density and high-pressure applications.

  • Stainless Steel MagnaLine Float

    Rugged 316/316L stainless steel construction designed for dependable performance in general industrial process services.

  • High-Pressure MagnaLine Float

    Reinforced float with ball-segment geometry for high-pressure service.

ClearView™ Indicator System

High-Visibility Process Isolation

The ClearView™ system delivers clear, continuous local level indication without mechanical linkages or process penetration. Driven by the internal float’s magnetic field, the external indicator remains completely isolated from the process, ensuring reliable performance unaffected by pressure, temperature, or aggressive fluid conditions. Multiple indicator styles, robust housing materials, sealing options, and temperature ratings are available to suit a wide range of operating environments.

Custom Scales and Readout Units

Indicator assemblies may be supplied with custom scale markings tailored to application requirements. Standard linear units are available in inches, feet, or metric, alongside dual scales or volumetric readouts (gallons, liters) derived from vessel geometry.

Custom scales are generated based on supplied drawings, strapping tables, or dimensional data to ensure accurate correlation between the indicated level and actual vessel volume. This enables direct interpretation of level information in application-specific units without manual conversion.

  • Black etched aluminum scale indicator with high-contrast markings, resistant to UV exposure, abrasion, and chemical attack for long-term industrial service.

  • Transparent PVC indicator housing without scale, providing direct visual level indication for chemically aggressive, low-temperature service.

  • Silver etched aluminum scale indicator providing durable, high-visibility level indication for general industrial environments.

  • PVC roller-style indicator with integrated scale, designed for corrosive service at lower operating temperatures.

  • Hermetically sealed indicator assembly with stainless steel scale and frame, intended for harsh, humid, or washdown environments.

  • Indicator assembly with dual scale markings for simultaneous display of level in two units, such as height and volume, based on application data.

Principle of Operation

How It Works

1. Float Mechanism

  • A sealed MagnaLine™ float containing a permanent magnetic assembly is designed to remain buoyant within the process liquid based on the fluid’s specific gravity.

  • As the liquid level rises or falls, the float moves correspondingly within the chamber.

2. Magnetic Coupling

  • The float’s magnetic field is coupled to the external ClearView™ visual indicator mounted on the chamber.

  • This ensures the indicator moves synchronously with the float, providing an accurate representation of liquid level without direct process contact.

3. Visual Indication

  • The indicator is comprised of rotating flags or rollers in contrasting colors that change position to reflect liquid and vapor levels.

  • This provides clear, continuous visual indication without direct process contact, supporting reliable operation across typical pressure and temperature ranges.

Sealed and Non-Invasive Design

  • Fully Contained Process: The process fluid remains completely contained within the chamber.

  • No Wetted Indication Components: No glass, probes, or electronics are exposed to the process.

  • Leak and Emissions Reduction: Eliminates potential leak paths, emissions, and contamination risk.

Magnetic level gauges provide a sealed, non-invasive method of liquid level indication for industrial process applications where safety, reliability, and maintenance access are critical. Here’s why MLGs are the superior choice:

Why Use Magnetic Level Gauges?

Improved Safety Compared to Sight Glasses

  • No Fragile Glass: Removes glass components from the process line entirely.

  • Shatter Risk Elimination: Avoids failures caused by pressure spikes, thermal shock, or impact.

  • Reduced Exposure Risk: Minimizes personnel exposure to hazardous or corrosive fluids.

Low Maintenance and Long Service Life

  • Externally Mounted Components: Indicator assemblies remain isolated from the process fluid.

  • No Degrading Wetted Parts: Eliminates seals, gaskets, or electronics that deteriorate over time.

  • Simplified Inspection: Reduces inspection effort and overall lifecycle maintenance requirements.

Mechanical Reliability

  • Magnetically Coupled Operation: Uses a float and external indicator linked through magnetic coupling.

  • Non-Electronic Indication: No electronics, power supply, or calibration required for local indication.

  • Harsh Environment Performance: Maintains reliable operation where electronic sensors may struggle.

Technical Specifications

Chamber Configurations

Side-Side, Top-Bottom, Top-Side, Bottom-Side Dual-chamber construction available with dedicated float chamber and secondary instrumentation chamber (available upon request)

Chamber Diameters

1.5", 2" (schedule and material per design requirements) Larger diameters available upon request

Measuring Range

Standard lengths up to 18.5 ft (5.6 m), depending on material and support conditions. Extended lengths available upon request

Accuracy

Typical: ±10 mm (±0.4 in), subject to float design and application conditions

Specific Gravity Range

≥ 0.59 (minimum), subject to float design and application conditions

Pressure Range

Full vacuum to 150 psig (10 bar), depending on material, temperature, and configuration

Temperature Range

–20 °C to +120 °C (–4 °F to +248 °F), depending on chamber material and application conditions

Float Materials

Solid Thermoplastics: PVDF, PTFE, PVC, PP

Engineered Alloys: SS316, Titanium (available upon request)

Chamber Materials

PVC, CPVC, PVDF

Optional linings and coatings available upon request (e.g., ECTFE/Halar®, ETFE/Tefzel®)

Process Connections

Flanged or threaded (NPT)

Sizes: ½", ¾", 1", 1.5", 2”

Larger sizes and custom connections available upon request, subject to application review.

Indicator Options

Standard Indicator Assemblies

PVC flag indicators with transparent PVC housing, max 80 °C

PVC roller indicators with PVC housing and PVC scale, max 80 °C

Optional Indicator Assemblies (Available upon Request)

Stainless steel flag indicators with metallic housing, max 300 °C

Hermetically sealed indicator housings, max 80 °C or 300 °C

Scale Options

Feet & Inches (Imperial)

Meters/Centimeters (Metric)

Percent (0–100%)

Volume indication (Gallons or Liters, based on customer-provided reference)

Custom

No Scale

Scale Material

Etched aluminum scale resistant to UV exposure, abrasion, and chemical attack. Marking compliant with MIL-STD-130N and related identification standards. Optional non-metallic scales available for enhanced chemical resistance.

Vent & Drain Options

Threaded (MNPT or FNPT) or flanged connections

Standard Sizes: ½", ¾"

Alternate connection types (e.g., SAE) and larger sizes available upon request, subject to application review

Surface Finishes & Treatments

Supplied in as-molded finish Optional external coating or paint available for identification or color coding

Testing & Quality Assurance

Visual inspection of solvent- and fusion-bonded joints and overall assembly

Leak testing by 24-hour water fill inspection

Additional inspection methods available upon request, where applicable

Product Literature & Downloads

Technical documentation provided for application review, specification, and quotation support.

Product Overview

Specification Sheet

Ready to Specify Polysight?

Request a Quote